theiceman

Hi Guys

Pete was helping me with a few leaks but it is hard to PM a pic so thought i would share for all to see.

Pete I definitely have identifed my cam tower to chain box leak on both sides as you had suspected. Not a lot but a definite trail down the inside (front) of the chain box. Fair enough. I also sourced some rocker shaft seals. I amnot convinced it is leaking here but it can not hurt right ? can these be changed with the engine in the car ?

one of the more frustrating leaks is very hard to find. I have posted a pic here of where the oil always forms in huge drips.
I got this pic off fleabay to show where. My oil return lines are clean and don't look like they are leaking. I stuffed tissue all around the space where the tube goes into the tower and it was dry , but I still had the drop where my arrow shows in the pic . it is always on the cylinder rear most on the car. Do you think this could be the rocker arms leaking and runing down ? I have no oil pooling belw the end of the shafts so I am a little stumped. Could I be leaking between the cam tower and the head? i this a common area for leaks

I have seen this leak on several cars and am wondering if anyone else has seen this?

Peter Zimmermann

ice: Greetings. The drip that you describe can definitely be a rocker shaft, but the tower to head is also a small possibility. If your engine has been apart the chance of leakage from tower to head becomes greater, because most people will use Curil T at that area during reassembly. Unlike Curil T, LocTite 574 is a far superior product, and if used properly will never leak. Curil T is OK, but 574 has proven itself over many years. Another issue that can result in tower to head seepage is poor cleaning techniques, and failure to use laquer thinner or MEK as the final cleaning solution. Oil based solvents will never get those non-gasketed surfaces clean enough. While we're on the subject of gaskets, no sealant should be used on any of the top end gaskets (chain box to case, cam o-ring holder to tower, etc.), those gaskets are all designed to be installed dry, sealant disturbs that and part joints will start to leak somewhere down the road. If the gaskets are used dry they will never leak. One more comment on your leak, are you absolutely sure that everything on the top of the engine, near the thermostat area, is dry? Also, do you get crankcase blowby in your airbox, I know that a while ago you weren't sure if your oil level was correct. If the bottom of the inside of the airbox is actually wet some of that can find its way on to the top of the engine.
You can do any/all rocker shaft reseals, and cam o-rings, with the engine in the car, but without a hoist it's no fun. You mentioned shaft seals - they're OK but I've got a better way, in my opinion, of course, to get that area dry!

theiceman

Pete:

To address some of oyur questions:

My car has definitely been apart as there is sealent evident on the engine casing and gearbox. I do not know the specific history of the car however.
Great info on the gaskets as I have all kinds getting ready to do.

Of course checking the thermosat area on this SC has been a nightmare , I just can not see in. I am assuming ( I know that is killer ) it is dry as the cylinder near the front of the car are dry and i thought this is where I wold see evidence of leaks in this area, no oil dripping down onto the collector area where all 3 pipes come together. If you know of a way for me to contourt my body so I can check further please let me know..
I am pretty sure I don't have blow by but you never know. Everything looks spotless from up top. It is just down below that I am leaking a fair bit.

You have been teasing me a while about sealing those rocker shafts .... please shar.. If you have a good solution I am all ears. I think taking the valve covers off, sealing the shafts and doinf my valve adjustment is a great first effort. If the leak continues I iwll look at going further. If it means resealing the towers , then of course the engine is coming out and the cam o -rings will be getting done.

I just can't see retiming the cams in the car for a first timer.

Thanks as always for oyur help Pete.

Peter Zimmermann

Leaky rocker shafts. First, if you don't see pooling of oil at the recessed end, or an area below the protruding end that's been washed clean, that shaft isn't leaking. If you find one that is, put the engine on TDC for that cylinder and loosen that rocker shaft bolt. You'll need high quality 5mm and 8mm hand allen wrenches. If the bolt is too tight hold the 8mm end firmly, and slide the box end of a 13mm wrench down over the end of the 5mm allen, which makes an excellent extension. Once loose spritz both ends of the shaft with a good aerosol parts cleaner and push the shaft out. This might take a little effort, however you get it done be very careful to not scratch the shaft bore. Once loose clean the shaft, bore, and rocker thoroughly, with a final wipe of laquer thinner (use Q-Tips in the aluminum bore). Inspect the shaft for wear, you can do a light polish but it's usually not necessary. If it's suitable to reuse, and the bore is not damaged (engines that have been apart frequently have deep scratches in the shaft bores - I know a "mechanic" that used to drive shafts out with a punch, without loosening the bolt or cleaning the bore first - he proclaimed that he could take a 911 engine apart faster than anybody in the country!) you're ready to put it back together. Open your LocTite 574, and cut the furry ends off of a few Q-Tips. Bend the Q-Tip sticks about a third of the way from one end, at about a thirty degree angle. Hold the tip of the long end and slide the bent end into the shaft bore, you want it so that you can load it with 574 and coat (lightly and completely) the first 10mm of the bore (only the side of the rocker arm that the shaft will contact last during installation)with the sealant. The object will be to put the rocker arm in position, no 574 should touch it or its bushing area, and slide the shaft partially in to position through the still-dry side of the bore. You will coat only the bore opposite the side for shaft entry, after the shaft passes through the rocker arm bushing it will slide through the 574, creating a seal. But before you push the shaft all the way into position you must coat the other, dry, end of the shaft with 574, outboard of the expansion groove, while its still visible. As you continue to push the shaft into position the 574 will seal from bore to shaft at one end, and from shaft to bore at the push end. Important note, do not push the shaft too far in, because when you pull it back a little it can drag some 574 with it, right into the rocker arm - that's bad. This might sound hard, but it isn't, once you've done two or three it gets much easier. A couple of thoughts; (1) light scratches in the bore will be filled with the 574, but you have to work quickly to tighten the shaft bolt before the 574 sets up. (2) You can determine the correct position of the rocker shaft by holding it up to the cam tower, directly over the shaft bore. You want the two expansion grooves equi-distant from the rocker arm opening, so the ideal is that you'll see a couple of millimeters of the shaft, actually, the conical that the bolt fits inside of, protrude from the narrow side of the bore, the other end of the shaft will be recessed. (As you look at an installed rocker arm the cam tower at one side will be significantly narrower than the other side). (3) Rocker shaft bolts are tightened by holding the 8mm side and turning the 5mm side. You probably won't be able to find an 8mm allen short enough to be easy to use, I made one by removing all but about 20mm of the short leg - I bought my wrenches from SnapOn. You want good ones because you don't want to round off the allen recesses in the shaft hardware. (4) Always polish, on a wire wheel, the outside of the conical and nut, if you don't a burr can catch on the inside of the rocker shaft and give you a false tight.
Well, I've probably forgotten to mention something, I'll review this post later and add as necessary.
Cheers!

ebsalem

Pete,

How does using the 574 compare to using the rubber gaskets in the rocker shaft grooves?

dsmith

ice/pete, how nice of you guys to start a thread on this, as i just pulled my motor to do the cam seals. i have a big leak at high rpms, and have checked the rocker shafts. do you mind if i keep my experience/questions here also?

so, here's my parts list:
2 cam seals 99970146840
2 gaskets 93010519705
1 set of chain housing cover gaskets 100912181
1 set valve cover hardware
1 oil filter
10ish qts oil

and tools:
1 cam bar
1 dial guage
1 z block gauge holder

still need?
2 dowl pins for sprockets
1 mechanical tensioner to help on right side

pete, so you say no lube/sealant on the orings and gaskets? no copper spray or curil T, etc that i've read about?

i really don't want to do this again until a topend rebuild.
thanks,
David

theiceman

Welcome aboard the thread David, sounds like you and I share the same leaks... I have heard you can use a drill bit for the dowel is is is only used for alignment.
Do you have the crows foot and socket to tighten up the cam sprocket nut ? I think some years require different tools.

I have also heard conflictin reports about the small spacers you can put in the tensioners to limit damage ( basically tensioner travel ) on a failure. Some reports say it is for mechanical tensioners also , but I also heard they can be put on hydraulic tensioner. ( don't see why not really ) especially if you are in there anyway.

Wow Pete I actually understood that whole thing and the theory of assembly with he 574. I think I need to get the covers off and visualize some of it as far as the tools and hardware go.

great post .. definitely a keeper thread. I think I may just reseal them all to elliminate this from the equation with my oil leaks .. especially if i can do it in the car.

dsmith

I've got an 83, so no crows foot for me. I did the hydraulic tensioner upgrade last year. Don't think I'll put on the collars. Hindsight being 20/20, I would have done the cam seals and sealed the rocker shafts, had I known. Oh well, I needed something to do between races.

Thanks for the drill bit idea. Plenty of those laying around.

FYI, while eliminating leak possibilities, I checked the #1 exhaust rocker shaft in the car and it was a major PITA. Took me longer to R&R that thing and adjust the valve than it takes to pull the motor! I think I'll do a quick heater hose clean up with those PartsHeaven pieces too.

Pete, how easy is it to clean the 574 out later? If not leaking, I'm guessing I should wait until a top end rebuild to save some cleaning?
Thanks,
David

theiceman

heater hose clean up ?

does that mean removing the heater blower completely ??? , oh yeah Texas .... forget I asked ..

Peter Zimmermann

David: Correct, no sealant on any of the top end o.e. gaskets. Adding sealant prevents the gaskets from sealing as designed. I'm not sure if old style paper gaskets still exist (I haven't seen any in 15+ years), but if you have some throw them away. However, one thing that will make assembly easier is to put a very thin coating of white grease on the cam o-rings, and then use the three 6mm bolts to tighten them into place gradually. Use care, every once in a while an o-ring will get hung up on the chain box opening and you'll need a little tool (I use a small flat-bladed screwdriver) to push the ring gently into position. I'm curious about sprocket dowel pins, what do you mean? If you're referring to the chain sprockets on the cam, those pins are open sided and threaded internally. It just so happens that a good old W5DC Bosch plug has the correct size thread on its small tip (unscrew the plug reach adaptor from the plug), just screw the spark plug into the pin and pull it out. The dowel pins are almost always in perfect condition. One thing that you and ice might run into is that you might find wear on the sprocket shim that's beveled. When you remove your sprockets you will find between two and five thin shims + (1) thick one who's beveled side should face the cam tower. Those thick shims can wear and if they have a step on them should be replaced. Keep track of those shims - it'll save you a lot of work!

ice: David's right, the 1,2 & 3 exhaust rockers are very difficult to get to without first removing the cat, pre-muffler, or whatever you have. This is why the job is much easier with the car on a lift and you standing under it. Before you do all your rocker shafts be sure to check your cam lobes for pitting! One thing that I forgot on my earlier post is just before you put the rocker covers back on squirt oil into the hole in each rocker, as well as on the sides of each rocker.

574 clean-up isn't really more difficult than other sealers, you just have to be careful, when you work with aluminum surfaces, that you don't scratch them. Aerosol parts cleaner, pipe-stem brushes and other similar tools are your friends!

Regarding tensioner guards, those apply to 930 tensioners. I guess that they're OK, but I never used them. The best solution, of course, is to update to oil-fed tensioners.

theiceman

I find it difficult to see the cam lobes while the rocker is in place, do you mean to check it and the rocker while it is out?

also I have a bypass pipe and just replaced all the hardware very recently so I can whip it off in 5 minutes.

dsmith

Pete, thanks again for participating! I wasn't sure if the sprocket pins were on the car, or if they were a tool used when setting the timing. I'll know soon enough when I open it up. I forgot about the shims, so thanks again.

We have the ALMS/Cart race this weekend, but I still may start on it Sunday.
'Til then,
David

ron mcatee

Ice, try using a small mirror and a drop light to look down into that thermostat opening. On my 88 Carrera, I managed to get in far enough to see it, but yours may be more difficult. I don't know much about SC's. Good luck.

theiceman

SCs are freakin impossible ..... do you thing mirror woud help here ? :-)

theiceman

Ps that's an old pic .. looks much better now with all the bits on ..